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  <h1>Source code for kospeech.data.audio.feature</h1><div class="highlight"><pre>
<span></span><span class="kn">import</span> <span class="nn">torch</span>
<span class="kn">import</span> <span class="nn">librosa</span>
<span class="kn">import</span> <span class="nn">platform</span>
<span class="kn">import</span> <span class="nn">numpy</span> <span class="k">as</span> <span class="nn">np</span>
<span class="kn">from</span> <span class="nn">torch</span> <span class="k">import</span> <span class="n">Tensor</span><span class="p">,</span> <span class="n">FloatTensor</span>

<span class="c1"># torchaudio is only supported on Linux (Linux, Mac)</span>
<span class="k">if</span> <span class="n">platform</span><span class="o">.</span><span class="n">system</span><span class="p">()</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span> <span class="o">==</span> <span class="s1">&#39;linux&#39;</span><span class="p">:</span>
    <span class="k">try</span><span class="p">:</span>
        <span class="kn">import</span> <span class="nn">torchaudio</span>
    <span class="k">except</span> <span class="ne">ImportError</span><span class="p">:</span>
        <span class="k">raise</span> <span class="ne">ImportError</span><span class="p">(</span><span class="s2">&quot;SpectrogramPaser requires torchaudio package.&quot;</span><span class="p">)</span>


<div class="viewcode-block" id="Spectrogram"><a class="viewcode-back" href="../../../../Data.html#kospeech.data.audio.feature.Spectrogram">[docs]</a><span class="k">class</span> <span class="nc">Spectrogram</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
    <span class="sd">&quot;&quot;&quot;</span>
<span class="sd">    Create a spectrogram from a audio signal.</span>

<span class="sd">    Args: sample_rate, window_size, frame_shift, feature_extract_by</span>
<span class="sd">        sample_rate (int): Sample rate of audio signal. (Default: 16000)</span>
<span class="sd">        frame_length (int): frame length for spectrogram (ms) (Default : 20)</span>
<span class="sd">        frame_shift (int): Length of hop between STFT windows. (ms) (Default: 10)</span>
<span class="sd">    &quot;&quot;&quot;</span>
    <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">sample_rate</span><span class="p">:</span> <span class="nb">int</span> <span class="o">=</span> <span class="mi">16000</span><span class="p">,</span>
                 <span class="n">frame_length</span><span class="p">:</span> <span class="nb">int</span> <span class="o">=</span> <span class="mi">20</span><span class="p">,</span> <span class="n">frame_shift</span><span class="p">:</span> <span class="nb">int</span> <span class="o">=</span> <span class="mi">10</span><span class="p">,</span>
                 <span class="n">feature_extract_by</span><span class="p">:</span> <span class="nb">str</span> <span class="o">=</span> <span class="s1">&#39;torch&#39;</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="kc">None</span><span class="p">:</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">sample_rate</span> <span class="o">=</span> <span class="n">sample_rate</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">feature_extract_by</span> <span class="o">=</span> <span class="n">feature_extract_by</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span>

        <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">feature_extract_by</span> <span class="o">==</span> <span class="s1">&#39;kaldi&#39;</span><span class="p">:</span>
            <span class="c1"># torchaudio is only supported on Linux (Linux, Mac)</span>
            <span class="k">assert</span> <span class="n">platform</span><span class="o">.</span><span class="n">system</span><span class="p">()</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span> <span class="o">==</span> <span class="s1">&#39;linux&#39;</span> <span class="ow">or</span> <span class="n">platform</span><span class="o">.</span><span class="n">system</span><span class="p">()</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span> <span class="o">==</span> <span class="s1">&#39;darwin&#39;</span>
            <span class="bp">self</span><span class="o">.</span><span class="n">frame_length</span> <span class="o">=</span> <span class="n">frame_length</span>
            <span class="bp">self</span><span class="o">.</span><span class="n">frame_shift</span> <span class="o">=</span> <span class="n">frame_shift</span>

        <span class="k">else</span><span class="p">:</span>
            <span class="bp">self</span><span class="o">.</span><span class="n">n_fft</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="nb">round</span><span class="p">(</span><span class="n">sample_rate</span> <span class="o">*</span> <span class="mf">0.001</span> <span class="o">*</span> <span class="n">frame_length</span><span class="p">))</span>
            <span class="bp">self</span><span class="o">.</span><span class="n">hop_length</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="nb">round</span><span class="p">(</span><span class="n">sample_rate</span> <span class="o">*</span> <span class="mf">0.001</span> <span class="o">*</span> <span class="n">frame_shift</span><span class="p">))</span>

    <span class="k">def</span> <span class="nf">__call__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">signal</span><span class="p">):</span>
        <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">feature_extract_by</span> <span class="o">==</span> <span class="s1">&#39;kaldi&#39;</span><span class="p">:</span>
            <span class="n">spectrogram</span> <span class="o">=</span> <span class="n">torchaudio</span><span class="o">.</span><span class="n">compliance</span><span class="o">.</span><span class="n">kaldi</span><span class="o">.</span><span class="n">spectrogram</span><span class="p">(</span><span class="n">Tensor</span><span class="p">(</span><span class="n">signal</span><span class="p">)</span><span class="o">.</span><span class="n">unsqueeze</span><span class="p">(</span><span class="mi">0</span><span class="p">),</span>
                                                                  <span class="n">frame_length</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">frame_length</span><span class="p">,</span>
                                                                  <span class="n">frame_shift</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">frame_shift</span><span class="p">,</span>
                                                                  <span class="n">sample_frequency</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">sample_rate</span><span class="p">)</span><span class="o">.</span><span class="n">transpose</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
        <span class="k">else</span><span class="p">:</span>
            <span class="n">spectrogram</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">stft</span><span class="p">(</span><span class="n">Tensor</span><span class="p">(</span><span class="n">signal</span><span class="p">),</span> <span class="bp">self</span><span class="o">.</span><span class="n">n_fft</span><span class="p">,</span> <span class="n">hop_length</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">hop_length</span><span class="p">,</span>
                                     <span class="n">win_length</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">n_fft</span><span class="p">,</span> <span class="n">window</span><span class="o">=</span><span class="n">torch</span><span class="o">.</span><span class="n">hamming_window</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">n_fft</span><span class="p">),</span>
                                     <span class="n">center</span><span class="o">=</span><span class="kc">False</span><span class="p">,</span> <span class="n">normalized</span><span class="o">=</span><span class="kc">False</span><span class="p">,</span> <span class="n">onesided</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
            <span class="n">spectrogram</span> <span class="o">=</span> <span class="p">(</span><span class="n">spectrogram</span><span class="p">[:,</span> <span class="p">:,</span> <span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">pow</span><span class="p">(</span><span class="mi">2</span><span class="p">)</span> <span class="o">+</span> <span class="n">spectrogram</span><span class="p">[:,</span> <span class="p">:,</span> <span class="mi">1</span><span class="p">]</span><span class="o">.</span><span class="n">pow</span><span class="p">(</span><span class="mi">2</span><span class="p">))</span><span class="o">.</span><span class="n">pow</span><span class="p">(</span><span class="mf">0.5</span><span class="p">)</span>
            <span class="n">spectrogram</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">log1p</span><span class="p">(</span><span class="n">spectrogram</span><span class="o">.</span><span class="n">numpy</span><span class="p">())</span>

        <span class="k">return</span> <span class="n">spectrogram</span></div>


<div class="viewcode-block" id="MelSpectrogram"><a class="viewcode-back" href="../../../../Data.html#kospeech.data.audio.feature.MelSpectrogram">[docs]</a><span class="k">class</span> <span class="nc">MelSpectrogram</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
    <span class="sd">&quot;&quot;&quot;</span>
<span class="sd">    Create MelSpectrogram for a raw audio signal. This is a composition of Spectrogram and MelScale.</span>

<span class="sd">    Args: sample_rate, n_mels, frame_length, frame_shift, feature_extract_by</span>
<span class="sd">        sample_rate (int): Sample rate of audio signal. (Default: 16000)</span>
<span class="sd">        n_mels (int):  Number of mfc coefficients to retain. (Default: 80)</span>
<span class="sd">        frame_length (int): frame length for spectrogram (ms) (Default : 20)</span>
<span class="sd">        frame_shift (int): Length of hop between STFT windows. (ms) (Default: 10)</span>
<span class="sd">        feature_extract_by (str): which library to use for feature extraction(default: librosa)</span>
<span class="sd">    &quot;&quot;&quot;</span>
    <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">sample_rate</span><span class="o">=</span><span class="mi">16000</span><span class="p">,</span> <span class="n">n_mels</span><span class="o">=</span><span class="mi">80</span><span class="p">,</span> <span class="n">frame_length</span><span class="o">=</span><span class="mi">20</span><span class="p">,</span> <span class="n">frame_shift</span><span class="o">=</span><span class="mi">10</span><span class="p">,</span> <span class="n">feature_extract_by</span><span class="o">=</span><span class="s1">&#39;librosa&#39;</span><span class="p">):</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">sample_rate</span> <span class="o">=</span> <span class="n">sample_rate</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">n_mels</span> <span class="o">=</span> <span class="n">n_mels</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">n_fft</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="nb">round</span><span class="p">(</span><span class="n">sample_rate</span> <span class="o">*</span> <span class="mf">0.001</span> <span class="o">*</span> <span class="n">frame_length</span><span class="p">))</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">hop_length</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="nb">round</span><span class="p">(</span><span class="n">sample_rate</span> <span class="o">*</span> <span class="mf">0.001</span> <span class="o">*</span> <span class="n">frame_shift</span><span class="p">))</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">feature_extract_by</span> <span class="o">=</span> <span class="n">feature_extract_by</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span>

        <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">feature_extract_by</span> <span class="o">==</span> <span class="s1">&#39;torchaudio&#39;</span><span class="p">:</span>
            <span class="c1"># torchaudio is only supported on Linux (Linux, Mac)</span>
            <span class="k">assert</span> <span class="n">platform</span><span class="o">.</span><span class="n">system</span><span class="p">()</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span> <span class="o">==</span> <span class="s1">&#39;linux&#39;</span> <span class="ow">or</span> <span class="n">platform</span><span class="o">.</span><span class="n">system</span><span class="p">()</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span> <span class="o">==</span> <span class="s1">&#39;darwin&#39;</span>

            <span class="bp">self</span><span class="o">.</span><span class="n">transforms</span> <span class="o">=</span> <span class="n">torchaudio</span><span class="o">.</span><span class="n">transforms</span><span class="o">.</span><span class="n">MelSpectrogram</span><span class="p">(</span><span class="n">sample_rate</span><span class="o">=</span><span class="n">sample_rate</span><span class="p">,</span> <span class="n">win_length</span><span class="o">=</span><span class="n">frame_length</span><span class="p">,</span>
                                                                   <span class="n">hop_length</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">hop_length</span><span class="p">,</span> <span class="n">n_fft</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">n_fft</span><span class="p">,</span>
                                                                   <span class="n">n_mels</span><span class="o">=</span><span class="n">n_mels</span><span class="p">)</span>
            <span class="bp">self</span><span class="o">.</span><span class="n">amplitude_to_db</span> <span class="o">=</span> <span class="n">torchaudio</span><span class="o">.</span><span class="n">transforms</span><span class="o">.</span><span class="n">AmplitudeToDB</span><span class="p">()</span>

    <span class="k">def</span> <span class="nf">__call__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">signal</span><span class="p">):</span>
        <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">feature_extract_by</span> <span class="o">==</span> <span class="s1">&#39;torchaudio&#39;</span><span class="p">:</span>
            <span class="n">melspectrogram</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">transforms</span><span class="p">(</span><span class="n">Tensor</span><span class="p">(</span><span class="n">signal</span><span class="p">))</span>
            <span class="n">melspectrogram</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">amplitude_to_db</span><span class="p">(</span><span class="n">melspectrogram</span><span class="p">)</span>
            <span class="n">melspectrogram</span> <span class="o">=</span> <span class="n">melspectrogram</span><span class="o">.</span><span class="n">numpy</span><span class="p">()</span>

        <span class="k">elif</span> <span class="bp">self</span><span class="o">.</span><span class="n">feature_extract_by</span> <span class="o">==</span> <span class="s1">&#39;librosa&#39;</span><span class="p">:</span>
            <span class="n">melspectrogram</span> <span class="o">=</span> <span class="n">librosa</span><span class="o">.</span><span class="n">feature</span><span class="o">.</span><span class="n">melspectrogram</span><span class="p">(</span><span class="n">signal</span><span class="p">,</span> <span class="n">sr</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">sample_rate</span><span class="p">,</span> <span class="n">n_mels</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">n_mels</span><span class="p">,</span>
                                                            <span class="n">n_fft</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">n_fft</span><span class="p">,</span> <span class="n">hop_length</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">hop_length</span><span class="p">)</span>
            <span class="n">melspectrogram</span> <span class="o">=</span> <span class="n">librosa</span><span class="o">.</span><span class="n">amplitude_to_db</span><span class="p">(</span><span class="n">melspectrogram</span><span class="p">,</span> <span class="n">ref</span><span class="o">=</span><span class="n">np</span><span class="o">.</span><span class="n">max</span><span class="p">)</span>

        <span class="k">else</span><span class="p">:</span>
            <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">&quot;Unsupported library : </span><span class="si">{0}</span><span class="s2">&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">feature_extract_by</span><span class="p">))</span>

        <span class="k">return</span> <span class="n">melspectrogram</span></div>


<div class="viewcode-block" id="MFCC"><a class="viewcode-back" href="../../../../Data.html#kospeech.data.audio.feature.MFCC">[docs]</a><span class="k">class</span> <span class="nc">MFCC</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
    <span class="sd">&quot;&quot;&quot;</span>
<span class="sd">    Create the Mel-frequency cepstrum coefficients (MFCCs) from an audio signal.</span>

<span class="sd">    Args: sample_rate, n_mfcc, frame_length, frame_shift, feature_extract_by</span>
<span class="sd">        sample_rate (int): Sample rate of audio signal. (Default: 16000)</span>
<span class="sd">        n_mfcc (int):  Number of mfc coefficients to retain. (Default: 40)</span>
<span class="sd">        frame_length (int): frame length for spectrogram (ms) (Default : 20)</span>
<span class="sd">        frame_shift (int): Length of hop between STFT windows. (ms) (Default: 10)</span>
<span class="sd">        feature_extract_by (str): which library to use for feature extraction(default: librosa)</span>
<span class="sd">    &quot;&quot;&quot;</span>
    <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">sample_rate</span><span class="o">=</span><span class="mi">16000</span><span class="p">,</span> <span class="n">n_mfcc</span><span class="o">=</span><span class="mi">40</span><span class="p">,</span> <span class="n">frame_length</span><span class="o">=</span><span class="mi">20</span><span class="p">,</span> <span class="n">frame_shift</span><span class="o">=</span><span class="mi">10</span><span class="p">,</span> <span class="n">feature_extract_by</span><span class="o">=</span><span class="s1">&#39;librosa&#39;</span><span class="p">):</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">sample_rate</span> <span class="o">=</span> <span class="n">sample_rate</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">n_mfcc</span> <span class="o">=</span> <span class="n">n_mfcc</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">n_fft</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="nb">round</span><span class="p">(</span><span class="n">sample_rate</span> <span class="o">*</span> <span class="mf">0.001</span> <span class="o">*</span> <span class="n">frame_length</span><span class="p">))</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">hop_length</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="nb">round</span><span class="p">(</span><span class="n">sample_rate</span> <span class="o">*</span> <span class="mf">0.001</span> <span class="o">*</span> <span class="n">frame_shift</span><span class="p">))</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">feature_extract_by</span> <span class="o">=</span> <span class="n">feature_extract_by</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span>

        <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">feature_extract_by</span> <span class="o">==</span> <span class="s1">&#39;torchaudio&#39;</span><span class="p">:</span>
            <span class="c1"># torchaudio is only supported on Linux (Linux, Mac)</span>
            <span class="k">assert</span> <span class="n">platform</span><span class="o">.</span><span class="n">system</span><span class="p">()</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span> <span class="o">==</span> <span class="s1">&#39;linux&#39;</span> <span class="ow">or</span> <span class="n">platform</span><span class="o">.</span><span class="n">system</span><span class="p">()</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span> <span class="o">==</span> <span class="s1">&#39;darwin&#39;</span>

            <span class="bp">self</span><span class="o">.</span><span class="n">transforms</span> <span class="o">=</span> <span class="n">torchaudio</span><span class="o">.</span><span class="n">transforms</span><span class="o">.</span><span class="n">MFCC</span><span class="p">(</span><span class="n">sample_rate</span><span class="o">=</span><span class="n">sample_rate</span><span class="p">,</span> <span class="n">n_mfcc</span><span class="o">=</span><span class="n">n_mfcc</span><span class="p">,</span>
                                                         <span class="n">log_mels</span><span class="o">=</span><span class="kc">True</span><span class="p">,</span> <span class="n">win_length</span><span class="o">=</span><span class="n">frame_length</span><span class="p">,</span>
                                                         <span class="n">hop_length</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">hop_length</span><span class="p">,</span> <span class="n">n_fft</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">n_fft</span><span class="p">)</span>

    <span class="k">def</span> <span class="nf">__call__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">signal</span><span class="p">):</span>
        <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">feature_extract_by</span> <span class="o">==</span> <span class="s1">&#39;torchaudio&#39;</span><span class="p">:</span>
            <span class="n">mfcc</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">transforms</span><span class="p">(</span><span class="n">FloatTensor</span><span class="p">(</span><span class="n">signal</span><span class="p">))</span>
            <span class="n">mfcc</span> <span class="o">=</span> <span class="n">mfcc</span><span class="o">.</span><span class="n">numpy</span><span class="p">()</span>

        <span class="k">elif</span> <span class="bp">self</span><span class="o">.</span><span class="n">feature_extract_by</span> <span class="o">==</span> <span class="s1">&#39;librosa&#39;</span><span class="p">:</span>
            <span class="n">mfcc</span> <span class="o">=</span> <span class="n">librosa</span><span class="o">.</span><span class="n">feature</span><span class="o">.</span><span class="n">mfcc</span><span class="p">(</span><span class="n">y</span><span class="o">=</span><span class="n">signal</span><span class="p">,</span> <span class="n">sr</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">sample_rate</span><span class="p">,</span> <span class="n">n_mfcc</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">n_mfcc</span><span class="p">,</span>
                                        <span class="n">n_fft</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">n_fft</span><span class="p">,</span> <span class="n">hop_length</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">hop_length</span><span class="p">)</span>

        <span class="k">else</span><span class="p">:</span>
            <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">&quot;Unsupported library : </span><span class="si">{0}</span><span class="s2">&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">feature_extract_by</span><span class="p">))</span>

        <span class="k">return</span> <span class="n">mfcc</span></div>


<div class="viewcode-block" id="FilterBank"><a class="viewcode-back" href="../../../../Data.html#kospeech.data.audio.feature.FilterBank">[docs]</a><span class="k">class</span> <span class="nc">FilterBank</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
    <span class="sd">&quot;&quot;&quot;</span>
<span class="sd">    Create a fbank from a raw audio signal. This matches the input/output of Kaldi’s compute-fbank-feats</span>

<span class="sd">    Args: sample_rate, n_mels, frame_length, frame_shift, feature_extract_by</span>
<span class="sd">        sample_rate (int): Sample rate of audio signal. (Default: 16000)</span>
<span class="sd">        n_mels (int):  Number of mfc coefficients to retain. (Default: 80)</span>
<span class="sd">        frame_length (int): frame length for spectrogram (ms) (Default : 20)</span>
<span class="sd">        frame_shift (int): Length of hop between STFT windows. (ms) (Default: 10)</span>
<span class="sd">    &quot;&quot;&quot;</span>
    <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">sample_rate</span><span class="o">=</span><span class="mi">16000</span><span class="p">,</span> <span class="n">n_mels</span><span class="o">=</span><span class="mi">80</span><span class="p">,</span> <span class="n">frame_length</span><span class="o">=</span><span class="mi">20</span><span class="p">,</span> <span class="n">frame_shift</span><span class="o">=</span><span class="mi">10</span><span class="p">):</span>
        <span class="c1"># torchaudio is only supported on Linux (Linux, Mac)</span>
        <span class="k">assert</span> <span class="n">platform</span><span class="o">.</span><span class="n">system</span><span class="p">()</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span> <span class="o">==</span> <span class="s1">&#39;linux&#39;</span> <span class="ow">or</span> <span class="n">platform</span><span class="o">.</span><span class="n">system</span><span class="p">()</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span> <span class="o">==</span> <span class="s1">&#39;darwin&#39;</span>

        <span class="bp">self</span><span class="o">.</span><span class="n">sample_rate</span> <span class="o">=</span> <span class="n">sample_rate</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">n_mels</span> <span class="o">=</span> <span class="n">n_mels</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">frame_length</span> <span class="o">=</span> <span class="n">frame_length</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">frame_shift</span> <span class="o">=</span> <span class="n">frame_shift</span>

    <span class="k">def</span> <span class="nf">__call__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">signal</span><span class="p">):</span>
        <span class="k">return</span> <span class="n">torchaudio</span><span class="o">.</span><span class="n">compliance</span><span class="o">.</span><span class="n">kaldi</span><span class="o">.</span><span class="n">fbank</span><span class="p">(</span><span class="n">Tensor</span><span class="p">(</span><span class="n">signal</span><span class="p">)</span><span class="o">.</span><span class="n">unsqueeze</span><span class="p">(</span><span class="mi">0</span><span class="p">),</span> <span class="n">num_mel_bins</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">n_mels</span><span class="p">,</span>
                                                 <span class="n">frame_length</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">frame_length</span><span class="p">,</span> <span class="n">frame_shift</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">frame_shift</span><span class="p">,</span>
                                                 <span class="n">window_type</span><span class="o">=</span><span class="s1">&#39;povey&#39;</span><span class="p">)</span><span class="o">.</span><span class="n">transpose</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span><span class="o">.</span><span class="n">numpy</span><span class="p">()</span></div>
</pre></div>

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